Biology vs Biochemistry vs Chemical Engineering?

I'm planning on going down the medical path. Will a Bachelor in each of these prepare me for the MCAT and what I'll see in medical school? Less importantly, how "sellable" are these degrees relative to each other (should the medical path not work out)?

Biology and biochemistry overlap in areas such as organic chemistry, cell bio, genetics, etc. Pure biology includes areas such as ecology, evolution, botany, etc. If you want to go to medical school, I would suggest biochemistry (or a pre-med program).

Chemical engineering is a different field altogether. I don't know much about this field but my good friend is a chemical engineer and does not know a thing about the medical field - his work is more about (what he calls) chemical processes. Most, if not all, of the engineering graduates I am friends with got a job right out of school, biology not so much.

I don't know enough about the various degrees to comment on each one's marketability, though engineering fields are generally pretty good for that.

As someone who planned for a long time to ultimately attend medical school, I'll second the biochemistry recommendation for preparation. Just using the local university and med school as an example, the biochemistry degree fills all the med school's requirements (specifically: a year each of English, chemistry, organic chemistry, biology, physics, and another science), throws in another useful sequence (namely, biochemistry itself), and leaves room for other possibly useful classes (anatomy/physiology, immunology, medical microbiology, endocrinology, etc).

Keep in mind that the MCAT is more a test of reasoning ability than it is a test of knowledge. While extra courses will undoubtedly help, the basic requirements for med school admission should be adequate if all else fails. Also, as I'm sure you realize, make sure you pay attention to things outside of your coursework as well. There are many many students with excellent numbers applying to med school every year, and only something like 50% of applicants are actually accepted. Work on becoming the most well-rounded person you can be.

biology degrees are a dime a dozen and most of those students are intellectual treestumps
biochemistry will hit all of your med prereqs but is amazingly boring (biochem & microbio is often useful for med students)
chem eng is highly marketable and depending on your school will cover roughly 75% of med school prereqs, not to mention that having such an undergrad degree will separate you from the applicant pool (in a pleasantly surprising way)